1. Field of the Invention
The present disclosure relates to dishwashers and, more particularly, to a drain valve for a dishwasher and associated apparatus and method.
2. Description of Related Art
A dishwasher is typically used to remove food soils and debris from the dishware therein. In doing so, however, various factors such as, for example, water consumption, energy consumption, and the duration of the wash cycle must be considered in determining the effectiveness of the dishwasher. These factors, namely power consumption, water consumption, etc., may be adversely affected by draining and re-filling the dishwasher (i.e., increased water usage, as well as energy usage due to the pump used for draining the water). As such, one area of interest is effective filtration of the wash water, since the water used for washing the dishware is often re-circulated over the dishware. Effective filtration leads to a more effective dishwashing since food soils are not re-circulated back over the dishware. In addition, less draining and re-filling conserves water and energy, and may help to reduce the overall duration of the wash cycle.
Effective filtration, in some instances, is combined with other measures such as, for example, turbidity monitoring and/or circulation pump condition sensing, with the goal of a high quality wash. In or during a typical “pre-wash” or “main wash” cycle segment, the wash water in the tub may be drained and re-filled one or more times so as to remove excessive soils that may degrade the wash quality, if re-circulated in the dishwasher, wherein such excessive soils are determined through, for example, turbidity monitoring and/or condition sensing of the circulation pump.
The circulation pump and the turbidity sensor are typically located with the sump of the dishwasher. In this regard, water entering the sump from the tub is typically subjected to different filtration aspects, such as a glass trap, a coarse filter, and/or a finer filter. As such, provisions are provided for filtering the wash water before the wash water enters the sump to be re-circulated by the circulation pump. However, the circulation pump outlet may also include filtration provisions in communication therewith, such as a soil collection chamber (i.e., a pressurized fine filter), through which a portion of the wash water may be directed for further filtration as the wash water is directed from the circulation pump outlet and through the hydraulic system (spray arms, etc.).
In instances where such filtration provisions are included in communication with the outlet of the circulation pump, situations may arise where such filtration provisions (i.e., the soil collection chamber or “pressurized fine filter”) may become clogged or otherwise restricted (i.e., in particularly heavy or extreme soil loads in the dishwasher). Often, this situation would manifest itself in the sensing of the turbidity of the wash water as being above a particular level, or the sensing of a starvation condition of the circulation pump motor. In those situations, the wash water may be at least partially drained (which may evacuate or flush the soil collection chamber or pressurized fine filter), and then clean water used to replaced the drained wash water. However, this may not necessarily resolve the problem of the clogged or restricted pressurized fine filter (i.e., may not remove the material causing the clog or restriction therein). Further, in evacuating or flushing the pressurized fine filter, the flow of the water to do so (i.e., as provided through the lower wash arm) is directed through the filtration surface and into the interior of the pressurized fine filter, and then through the interior of the pressurized fine filter to a drain port thereof leading to the house drain. As such, if the pressurized fine filter remains blocked or clogged, and the circulation pump continues to pump the wash water, all or part of the wash water may be forced out through the pressurized fine filter drain port and into the house drain, leaving the dishwasher in a starvation condition, with no wash water therein. Often, in such situations, the wash water and/or soil/debris/particles in or removed from the soil collection chamber may be particularly harsh, and may require special provisions for handling.
Thus, there exists a need for a drain valve for a dishwasher that is configured to withstand particulate matter in the dishwasher while preventing wash water from exiting the drain pump system when the circulation pump is in operation.